/***************************************************************************/
/*                                                                         */
/*  ftstream.c                                                             */
/*                                                                         */
/*    I/O stream support (body).                                           */
/*                                                                         */
/*  Copyright 2000-2002, 2004-2006, 2008-2011 by                           */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/


#include <ft2build.h>
#include FT_INTERNAL_STREAM_H
#include FT_INTERNAL_DEBUG_H


/*************************************************************************/
/*                                                                       */
/* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
/* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
/* messages during execution.                                            */
/*                                                                       */
#undef  FT_COMPONENT
#define FT_COMPONENT  trace_stream


FT_BASE_DEF( void )
FT_Stream_OpenMemory( FT_Stream stream,
                      const FT_Byte *base,
                      FT_ULong size )
{
    stream->base = ( FT_Byte * ) base;
    stream->size = size;
    stream->pos = 0;
    stream->cursor = 0;
    stream->read = 0;
    stream->close = 0;
}


FT_BASE_DEF( void )
FT_Stream_Close( FT_Stream stream )
{
    if ( stream && stream->close )
    {
        stream->close( stream );
    }
}


FT_BASE_DEF( FT_Error )
FT_Stream_Seek( FT_Stream stream,
                FT_ULong pos )
{
    FT_Error error = FT_Err_Ok;


    if ( stream->read )
    {
        if ( stream->read( stream, pos, 0, 0 ))
        {
            FT_ERROR(( "FT_Stream_Seek:"
                       " invalid i/o; pos = 0x%lx, size = 0x%lx\n",
                    pos, stream->size ));

            error = FT_Err_Invalid_Stream_Operation;
        }
    }
        /* note that seeking to the first position after the file is valid */
    else if ( pos > stream->size )
    {
        FT_ERROR(( "FT_Stream_Seek:"
                   " invalid i/o; pos = 0x%lx, size = 0x%lx\n",
                pos, stream->size ));

        error = FT_Err_Invalid_Stream_Operation;
    }

    if ( !error )
    {
        stream->pos = pos;
    }

    return error;
}


FT_BASE_DEF( FT_Error )
FT_Stream_Skip( FT_Stream stream,
                FT_Long distance )
{
    if ( distance < 0 )
    {
        return FT_Err_Invalid_Stream_Operation;
    }

    return FT_Stream_Seek( stream, ( FT_ULong ) ( stream->pos + distance ));
}


FT_BASE_DEF( FT_Long )
FT_Stream_Pos( FT_Stream stream )
{
    return stream->pos;
}


FT_BASE_DEF( FT_Error )
FT_Stream_Read( FT_Stream stream,
                FT_Byte *buffer,
                FT_ULong count )
{
    return FT_Stream_ReadAt( stream, stream->pos, buffer, count );
}


FT_BASE_DEF( FT_Error )
FT_Stream_ReadAt( FT_Stream stream,
                  FT_ULong pos,
                  FT_Byte *buffer,
                  FT_ULong count )
{
    FT_Error error = FT_Err_Ok;
    FT_ULong read_bytes;


    if ( pos >= stream->size )
    {
        FT_ERROR(( "FT_Stream_ReadAt:"
                   " invalid i/o; pos = 0x%lx, size = 0x%lx\n",
                pos, stream->size ));

        return FT_Err_Invalid_Stream_Operation;
    }

    if ( stream->read )
    {
        read_bytes = stream->read( stream, pos, buffer, count );
    }
    else
    {
        read_bytes = stream->size - pos;
        if ( read_bytes > count )
        {
            read_bytes = count;
        }

        FT_MEM_COPY( buffer, stream->base + pos, read_bytes );
    }

    stream->pos = pos + read_bytes;

    if ( read_bytes < count )
    {
        FT_ERROR(( "FT_Stream_ReadAt:"
                   " invalid read; expected %lu bytes, got %lu\n",
                count, read_bytes ));

        error = FT_Err_Invalid_Stream_Operation;
    }

    return error;
}


FT_BASE_DEF( FT_ULong )
FT_Stream_TryRead( FT_Stream stream,
                   FT_Byte *buffer,
                   FT_ULong count )
{
    FT_ULong read_bytes = 0;


    if ( stream->pos >= stream->size )
    {
        goto Exit;
    }

    if ( stream->read )
    {
        read_bytes = stream->read( stream, stream->pos, buffer, count );
    }
    else
    {
        read_bytes = stream->size - stream->pos;
        if ( read_bytes > count )
        {
            read_bytes = count;
        }

        FT_MEM_COPY( buffer, stream->base + stream->pos, read_bytes );
    }

    stream->pos += read_bytes;

    Exit:
    return read_bytes;
}


FT_BASE_DEF( FT_Error )
FT_Stream_ExtractFrame( FT_Stream stream,
                        FT_ULong count,
                        FT_Byte **pbytes )
{
    FT_Error error;


    error = FT_Stream_EnterFrame( stream, count );
    if ( !error )
    {
        *pbytes = ( FT_Byte * ) stream->cursor;

        /* equivalent to FT_Stream_ExitFrame(), with no memory block release */
        stream->cursor = 0;
        stream->limit = 0;
    }

    return error;
}


FT_BASE_DEF( void )
FT_Stream_ReleaseFrame( FT_Stream stream,
                        FT_Byte **pbytes )
{
    if ( stream && stream->read )
    {
        FT_Memory memory = stream->memory;

#ifdef FT_DEBUG_MEMORY
        ft_mem_free( memory, *pbytes );
        *pbytes = NULL;
#else
        FT_FREE( *pbytes );
#endif
    }
    *pbytes = 0;
}


FT_BASE_DEF( FT_Error )
FT_Stream_EnterFrame( FT_Stream stream,
                      FT_ULong count )
{
    FT_Error error = FT_Err_Ok;
    FT_ULong read_bytes;


    /* check for nested frame access */
    FT_ASSERT( stream && stream->cursor == 0 );

    if ( stream->read )
    {
        /* allocate the frame in memory */
        FT_Memory memory = stream->memory;


        /* simple sanity check */
        if ( count > stream->size )
        {
            FT_ERROR(( "FT_Stream_EnterFrame:"
                       " frame size (%lu) larger than stream size (%lu)\n",
                    count, stream->size ));

            error = FT_Err_Invalid_Stream_Operation;
            goto Exit;
        }

#ifdef FT_DEBUG_MEMORY
        /* assume _ft_debug_file and _ft_debug_lineno are already set */
        stream->base = (unsigned char*)ft_mem_qalloc( memory, count, &error );
        if ( error )
          goto Exit;
#else
        if ( FT_QALLOC( stream->base, count ))
        {
            goto Exit;
        }
#endif
        /* read it */
        read_bytes = stream->read( stream, stream->pos,
                                   stream->base, count );
        if ( read_bytes < count )
        {
            FT_ERROR(( "FT_Stream_EnterFrame:"
                       " invalid read; expected %lu bytes, got %lu\n",
                    count, read_bytes ));

            FT_FREE( stream->base );
            error = FT_Err_Invalid_Stream_Operation;
        }
        stream->cursor = stream->base;
        stream->limit = stream->cursor + count;
        stream->pos += read_bytes;
    }
    else
    {
        /* check current and new position */
        if ( stream->pos >= stream->size ||
             stream->size - stream->pos < count )
        {
            FT_ERROR(( "FT_Stream_EnterFrame:"
                       " invalid i/o; pos = 0x%lx, count = %lu, size = 0x%lx\n",
                    stream->pos, count, stream->size ));

            error = FT_Err_Invalid_Stream_Operation;
            goto Exit;
        }

        /* set cursor */
        stream->cursor = stream->base + stream->pos;
        stream->limit = stream->cursor + count;
        stream->pos += count;
    }

    Exit:
    return error;
}


FT_BASE_DEF( void )
FT_Stream_ExitFrame( FT_Stream stream )
{
    /* IMPORTANT: The assertion stream->cursor != 0 was removed, given    */
    /*            that it is possible to access a frame of length 0 in    */
    /*            some weird fonts (usually, when accessing an array of   */
    /*            0 records, like in some strange kern tables).           */
    /*                                                                    */
    /*  In this case, the loader code handles the 0-length table          */
    /*  gracefully; however, stream.cursor is really set to 0 by the      */
    /*  FT_Stream_EnterFrame() call, and this is not an error.            */
    /*                                                                    */
    FT_ASSERT( stream );

    if ( stream->read )
    {
        FT_Memory memory = stream->memory;

#ifdef FT_DEBUG_MEMORY
        ft_mem_free( memory, stream->base );
        stream->base = NULL;
#else
        FT_FREE( stream->base );
#endif
    }
    stream->cursor = 0;
    stream->limit = 0;
}


FT_BASE_DEF( FT_Char )
FT_Stream_GetChar( FT_Stream stream )
{
    FT_Char result;


    FT_ASSERT( stream && stream->cursor );

    result = 0;
    if ( stream->cursor < stream->limit )
    {
        result = *stream->cursor++;
    }

    return result;
}


FT_BASE_DEF( FT_UShort )
FT_Stream_GetUShort( FT_Stream stream )
{
    FT_Byte *p;
    FT_Short result;


    FT_ASSERT( stream && stream->cursor );

    result = 0;
    p = stream->cursor;
    if ( p + 1 < stream->limit )
    {
        result = FT_NEXT_USHORT( p );
    }
    stream->cursor = p;

    return result;
}


FT_BASE_DEF( FT_UShort )
FT_Stream_GetUShortLE( FT_Stream stream )
{
    FT_Byte *p;
    FT_Short result;


    FT_ASSERT( stream && stream->cursor );

    result = 0;
    p = stream->cursor;
    if ( p + 1 < stream->limit )
    {
        result = FT_NEXT_USHORT_LE( p );
    }
    stream->cursor = p;

    return result;
}


FT_BASE_DEF( FT_ULong )
FT_Stream_GetUOffset( FT_Stream stream )
{
    FT_Byte *p;
    FT_Long result;


    FT_ASSERT( stream && stream->cursor );

    result = 0;
    p = stream->cursor;
    if ( p + 2 < stream->limit )
    {
        result = FT_NEXT_UOFF3( p );
    }
    stream->cursor = p;
    return result;
}


FT_BASE_DEF( FT_ULong )
FT_Stream_GetULong( FT_Stream stream )
{
    FT_Byte *p;
    FT_Long result;


    FT_ASSERT( stream && stream->cursor );

    result = 0;
    p = stream->cursor;
    if ( p + 3 < stream->limit )
    {
        result = FT_NEXT_ULONG( p );
    }
    stream->cursor = p;
    return result;
}


FT_BASE_DEF( FT_ULong )
FT_Stream_GetULongLE( FT_Stream stream )
{
    FT_Byte *p;
    FT_Long result;


    FT_ASSERT( stream && stream->cursor );

    result = 0;
    p = stream->cursor;
    if ( p + 3 < stream->limit )
    {
        result = FT_NEXT_ULONG_LE( p );
    }
    stream->cursor = p;
    return result;
}


FT_BASE_DEF( FT_Char )
FT_Stream_ReadChar( FT_Stream stream,
                    FT_Error *error )
{
    FT_Byte result = 0;


    FT_ASSERT( stream );

    *error = FT_Err_Ok;

    if ( stream->read )
    {
        if ( stream->read( stream, stream->pos, &result, 1L ) != 1L )
        {
            goto Fail;
        }
    }
    else
    {
        if ( stream->pos < stream->size )
        {
            result = stream->base[ stream->pos ];
        }
        else
        {
            goto Fail;
        }
    }
    stream->pos++;

    return result;

    Fail:
    *error = FT_Err_Invalid_Stream_Operation;
    FT_ERROR(( "FT_Stream_ReadChar:"
               " invalid i/o; pos = 0x%lx, size = 0x%lx\n",
            stream->pos, stream->size ));

    return 0;
}


FT_BASE_DEF( FT_UShort )
FT_Stream_ReadUShort( FT_Stream stream,
                      FT_Error *error )
{
    FT_Byte reads[2];
    FT_Byte *p = 0;
    FT_Short result = 0;


    FT_ASSERT( stream );

    *error = FT_Err_Ok;

    if ( stream->pos + 1 < stream->size )
    {
        if ( stream->read )
        {
            if ( stream->read( stream, stream->pos, reads, 2L ) != 2L )
            {
                goto Fail;
            }

            p = reads;
        }
        else
        {
            p = stream->base + stream->pos;
        }

        if ( p )
        {
            result = FT_NEXT_USHORT( p );
        }
    }
    else
    {
        goto Fail;
    }

    stream->pos += 2;

    return result;

    Fail:
    *error = FT_Err_Invalid_Stream_Operation;
    FT_ERROR(( "FT_Stream_ReadUShort:"
               " invalid i/o; pos = 0x%lx, size = 0x%lx\n",
            stream->pos, stream->size ));

    return 0;
}


FT_BASE_DEF( FT_UShort )
FT_Stream_ReadUShortLE( FT_Stream stream,
                        FT_Error *error )
{
    FT_Byte reads[2];
    FT_Byte *p = 0;
    FT_Short result = 0;


    FT_ASSERT( stream );

    *error = FT_Err_Ok;

    if ( stream->pos + 1 < stream->size )
    {
        if ( stream->read )
        {
            if ( stream->read( stream, stream->pos, reads, 2L ) != 2L )
            {
                goto Fail;
            }

            p = reads;
        }
        else
        {
            p = stream->base + stream->pos;
        }

        if ( p )
        {
            result = FT_NEXT_USHORT_LE( p );
        }
    }
    else
    {
        goto Fail;
    }

    stream->pos += 2;

    return result;

    Fail:
    *error = FT_Err_Invalid_Stream_Operation;
    FT_ERROR(( "FT_Stream_ReadUShortLE:"
               " invalid i/o; pos = 0x%lx, size = 0x%lx\n",
            stream->pos, stream->size ));

    return 0;
}


FT_BASE_DEF( FT_ULong )
FT_Stream_ReadUOffset( FT_Stream stream,
                       FT_Error *error )
{
    FT_Byte reads[3];
    FT_Byte *p = 0;
    FT_Long result = 0;


    FT_ASSERT( stream );

    *error = FT_Err_Ok;

    if ( stream->pos + 2 < stream->size )
    {
        if ( stream->read )
        {
            if ( stream->read( stream, stream->pos, reads, 3L ) != 3L )
            {
                goto Fail;
            }

            p = reads;
        }
        else
        {
            p = stream->base + stream->pos;
        }

        if ( p )
        {
            result = FT_NEXT_UOFF3( p );
        }
    }
    else
    {
        goto Fail;
    }

    stream->pos += 3;

    return result;

    Fail:
    *error = FT_Err_Invalid_Stream_Operation;
    FT_ERROR(( "FT_Stream_ReadUOffset:"
               " invalid i/o; pos = 0x%lx, size = 0x%lx\n",
            stream->pos, stream->size ));

    return 0;
}


FT_BASE_DEF( FT_ULong )
FT_Stream_ReadULong( FT_Stream stream,
                     FT_Error *error )
{
    FT_Byte reads[4];
    FT_Byte *p = 0;
    FT_Long result = 0;


    FT_ASSERT( stream );

    *error = FT_Err_Ok;

    if ( stream->pos + 3 < stream->size )
    {
        if ( stream->read )
        {
            if ( stream->read( stream, stream->pos, reads, 4L ) != 4L )
            {
                goto Fail;
            }

            p = reads;
        }
        else
        {
            p = stream->base + stream->pos;
        }

        if ( p )
        {
            result = FT_NEXT_ULONG( p );
        }
    }
    else
    {
        goto Fail;
    }

    stream->pos += 4;

    return result;

    Fail:
    *error = FT_Err_Invalid_Stream_Operation;
    FT_ERROR(( "FT_Stream_ReadULong:"
               " invalid i/o; pos = 0x%lx, size = 0x%lx\n",
            stream->pos, stream->size ));

    return 0;
}


FT_BASE_DEF( FT_ULong )
FT_Stream_ReadULongLE( FT_Stream stream,
                       FT_Error *error )
{
    FT_Byte reads[4];
    FT_Byte *p = 0;
    FT_Long result = 0;


    FT_ASSERT( stream );

    *error = FT_Err_Ok;

    if ( stream->pos + 3 < stream->size )
    {
        if ( stream->read )
        {
            if ( stream->read( stream, stream->pos, reads, 4L ) != 4L )
            {
                goto Fail;
            }

            p = reads;
        }
        else
        {
            p = stream->base + stream->pos;
        }

        if ( p )
        {
            result = FT_NEXT_ULONG_LE( p );
        }
    }
    else
    {
        goto Fail;
    }

    stream->pos += 4;

    return result;

    Fail:
    *error = FT_Err_Invalid_Stream_Operation;
    FT_ERROR(( "FT_Stream_ReadULongLE:"
               " invalid i/o; pos = 0x%lx, size = 0x%lx\n",
            stream->pos, stream->size ));

    return 0;
}


FT_BASE_DEF( FT_Error )
FT_Stream_ReadFields( FT_Stream stream,
                      const FT_Frame_Field *fields,
                      void *structure )
{
    FT_Error error;
    FT_Bool frame_accessed = 0;
    FT_Byte *cursor;

    if ( !fields || !stream )
    {
        return FT_Err_Invalid_Argument;
    }

    cursor = stream->cursor;

    error = FT_Err_Ok;
    do
    {
        FT_ULong value;
        FT_Int sign_shift;
        FT_Byte *p;


        switch ( fields->value )
        {
            case ft_frame_start:  /* access a new frame */
                error = FT_Stream_EnterFrame( stream, fields->offset );
                if ( error )
                {
                    goto Exit;
                }

                frame_accessed = 1;
                cursor = stream->cursor;
                fields++;
                continue;  /* loop! */

            case ft_frame_bytes:  /* read a byte sequence */
            case ft_frame_skip:   /* skip some bytes      */
            {
                FT_UInt len = fields->size;


                if ( cursor + len > stream->limit )
                {
                    error = FT_Err_Invalid_Stream_Operation;
                    goto Exit;
                }

                if ( fields->value == ft_frame_bytes )
                {
                    p = ( FT_Byte * ) structure + fields->offset;
                    FT_MEM_COPY( p, cursor, len );
                }
                cursor += len;
                fields++;
                continue;
            }

            case ft_frame_byte:
            case ft_frame_schar:  /* read a single byte */
                value = FT_NEXT_BYTE( cursor );
                sign_shift = 24;
                break;

            case ft_frame_short_be:
            case ft_frame_ushort_be:  /* read a 2-byte big-endian short */
                value = FT_NEXT_USHORT( cursor );
                sign_shift = 16;
                break;

            case ft_frame_short_le:
            case ft_frame_ushort_le:  /* read a 2-byte little-endian short */
                value = FT_NEXT_USHORT_LE( cursor );
                sign_shift = 16;
                break;

            case ft_frame_long_be:
            case ft_frame_ulong_be:  /* read a 4-byte big-endian long */
                value = FT_NEXT_ULONG( cursor );
                sign_shift = 0;
                break;

            case ft_frame_long_le:
            case ft_frame_ulong_le:  /* read a 4-byte little-endian long */
                value = FT_NEXT_ULONG_LE( cursor );
                sign_shift = 0;
                break;

            case ft_frame_off3_be:
            case ft_frame_uoff3_be:  /* read a 3-byte big-endian long */
                value = FT_NEXT_UOFF3( cursor );
                sign_shift = 8;
                break;

            case ft_frame_off3_le:
            case ft_frame_uoff3_le:  /* read a 3-byte little-endian long */
                value = FT_NEXT_UOFF3_LE( cursor );
                sign_shift = 8;
                break;

            default:
                /* otherwise, exit the loop */
                stream->cursor = cursor;
                goto Exit;
        }

        /* now, compute the signed value is necessary */
        if ( fields->value & FT_FRAME_OP_SIGNED )
        {
            value = ( FT_ULong ) (( FT_Int32 ) ( value << sign_shift ) >> sign_shift );
        }

        /* finally, store the value in the object */

        p = ( FT_Byte * ) structure + fields->offset;
        switch ( fields->size )
        {
            case ( 8 / FT_CHAR_BIT ):
                *( FT_Byte * ) p = ( FT_Byte ) value;
                break;

            case ( 16 / FT_CHAR_BIT ):
                *( FT_UShort * ) p = ( FT_UShort ) value;
                break;

            case ( 32 / FT_CHAR_BIT ):
                *( FT_UInt32 * ) p = ( FT_UInt32 ) value;
                break;

            default:  /* for 64-bit systems */
                *( FT_ULong * ) p = ( FT_ULong ) value;
        }

        /* go to next field */
        fields++;
    }
    while ( 1 );

    Exit:
    /* close the frame if it was opened by this read */
    if ( frame_accessed )
    {
        FT_Stream_ExitFrame( stream );
    }

    return error;
}


/* END */
